B61 nuclear bombThe B61 nuclear bomb is the primary thermonuclear gravity bomb in the United States Enduring Stockpile following the end of the Cold War. It is a low-to-intermediate yield strategic and tactical nuclear weapon featuring a two-stage radiation implosion design. The B61 is of the variable yield ("dial-a-yield" in informal military jargon) design with a yield of 0.3 to 340 kilotons in its various mods ("modifications").
B53 nuclear bombThe Mk/B53 was a high-yield thermonuclearbunker buster developed by the United States during the Cold War. Deployed on Strategic Air Command bombers, the B53, with a yield of 9 megatons, was the most powerful weapon in the U.S. nuclear arsenal after the last B41 nuclear bombs were retired in 1976. The B53 was the basis of the W-53 warhead carried by the Titan II missile, which was decommissioned in 1987.
Variable yieldVariable yield, or dial-a-yield, is an option available on most modern nuclear weapons. It allows the operator to specify a weapon's yield, or explosive power, allowing a single design to be used in different situations. For example, the Mod-10 B61 bomb had selectable explosive yields of 0.3, 5, 10 or 80 kilotons, depending on how the ground crew set a dial inside the casing when it was loaded onto an aircraft.B77 nuclear bombThe B77 was a nuclear bomb designed in 1974 to match the delivery capabilities of the B-1A bomber. This included the ability to be dropped from supersonic speeds at altitudes of 60,000 feet (18,000 m), or in a laydown delivery at high subsonic speeds at altitudes as low as 100 feet (30 m). Meant to replace the Mk 28 and Mk 43 in the strategic role, the program was cancelled in December 1977 due to rising costs and the cancellation of the bomber it had been designed to serve.
Enduring StockpileThe Enduring Stockpile is the name given to the United States' arsenal of nuclear weapons following the end of the Cold War. As of 2025, it comprises approximately 3,700 nuclear weapons. During the Cold War the United States produced over 70,000 nuclear weapons. By its end, the U.S. stockpile was about 23,000 weapons of 26 different types. The production of nuclear weapons ended in 1989, and since then existing weapons have been retired, dismantled, or mothballed.
Permissive action linkA permissive action link (PAL) is an access control security device for nuclear weapons. Its purpose is to prevent unauthorized arming or detonation of a nuclear weapon. The United States federal government's definition is: A device included in or attached to a nuclear weapon system to preclude arming and/or launching until the insertion of a prescribed discrete code or combination.
Thermonuclear weaponMulti-stage fusion-fission nuclear weaponDiagram of the US W88 warhead, a standard thermonuclear design.
TNT equivalentTNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. A ton of TNT equivalent is a unit of energy defined by convention to be 4.184 gigajoules (1 gigacalorie). It is the approximate energy released in the detonation of a metric ton (megagram) of trinitrotoluene (TNT). In other words, for each gram of TNT exploded, 4.184 kilojoules (or 1 kcal) of energy are released.
Lawrence Livermore National LaboratoryLawrence Livermore National Laboratory (LLNL) is a federally funded research and development center in Livermore, California, United States. Established in 1952, the laboratory is sponsored by the United States Department of Energy and administered privately by Lawrence Livermore National Security, LLC.
United StatesCountry primarily in North AmericaThe United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic consisting of 50 states and a federal capital district, Washington, D.C. The 48 contiguous states border Canada to the north and Mexico to the south, with the semi-exclave of Alaska in the northwest and the archipelago of Hawaii in the Pacific Ocean.
Unguided bombAn unguided bomb, also known as a free-fall bomb, gravity bomb, dumb bomb, or iron bomb, is an aircraft-dropped bomb (conventional or nuclear) that does not contain a guidance system and hence simply follows a ballistictrajectory. It includes all aircraft bombs in general service until the latter half of World War II, and the vast majority until the late 1980s, which were known simply as "bombs".
Rockwell B-1 LancerThe Rockwell B-1 Lancer is a supersonic variable-sweep wing heavy bomber used by the United States Air Force. It has been nicknamed the "Bone" (from "B-One"). As of 2026, it is one of the U.S. Air Force's three strategic bombers, along with the B-2 Spirit and the B-52 Stratofortress. It carries up to a 75,000-pound (34,000 kg) payload.*As an Amazon Associate I earn from qualifying purchases.